Deep slow earthquakes in Taiwan could hint at major quakes

TAIPEI (TVBS News) — Taiwan experiences frequent earthquakes, including a type called slow earthquakes, which release energy gradually. While these slow earthquakes are usually imperceptible, they can release energy equivalent to magnitude 4 to 7 earthquakes.

Professor Chen Hui-hsuan (陳卉瑄) from the Department of Earth Sciences at National Taiwan Normal University (台師大) noted that typical earthquakes release energy instantly, causing noticeable shaking. In contrast, slow earthquakes can take minutes, hours, or even weeks to complete, making them undetectable on the surface. 

These events occur deeper than regular earthquakes, reaching depths of up to 50 kilometers. In Taiwan, they primarily happen beneath the southern segment of the Central Mountain Range (中央山脈), peaking south of Yushan (玉山), also known as Jade Mountain.

Chen emphasized that although the significance of slow earthquakes is indirect, many cases show increased frequency and rupture speed of slow earthquakes before major quakes. However, these changes may span years rather than days before a significant event. More research is needed to determine if slow earthquakes are precursors to larger ones.

Following the April 3 earthquake in Hualien, discussions about the likelihood of strong quakes in Taiwan have resurfaced. Distinguished Professor Wu Yih-min (吳逸民) from National Taiwan University (台灣大學) stated that predicting the next major earthquake or identifying century-long cycles for faults like the Meishan fault is challenging. Wu stressed the importance of disaster preparedness across Taiwan's fault zones and the need for vigilance regarding volcanic activity.

Lin Cheng-horng (林正洪), a distinguished researcher at the Institute of Earth Sciences, Academia Sinica (中研院地球科學研究所), has monitored the Tatun Volcano in northern Taiwan. Lin believes that volcanic and seismic activities influence each other, necessitating proactive government disaster preparedness.